U.S. Pat. No. 5,655,256 is directed to a stationary rectangular brush for cleaning ducts that is attached to the terminal end of a vacuum hose. This brush loosens debris as die vacuum hose is moved within the duct. U.S. Pat. No. 5,802,667 discloses a duct cleaning device having a rotatable brush mounted in a helical configuration around the outer surface of a vacuum hose. The helical configuration of the brush causes rotation of the brush as it is advanced within a duct, however, there is no independent rotation of the brush if the vacuum hose is not moving within the duct, U.S. Pat. No. 5,608,941 and U.S. Pat. No. 4,792,363 describe a rotating brush positioned at the front of a vacuum hose for cleaning a duct interior. The brush rotates about a drive shaft that extends through the vacuum hose to a power source. An alternate external drive means is disclosed in U.S. Pat. No. 5,584,093 where the brush is rotated by incoming air pressure supplied by an air supply source through a hose mounted on the vacuum hose U.S. Pat. No. 5,109,567 teaches a duct cleaning device having rotating tubes disposed at the leading end of a vacuum hose. The tubes are connected to a compressed air source and the pressure caused by forcing compressed air through the tubes causes rotation of the tubes within the duct. A similar approach and device is taught in CA U.S. Pat. No. 2,221,385.
U.S. Pat. No. 5,107,568 relates to a duct cleaning device having a single brush extending from the leading end of a vacuum hose. The brush is attached to a flexible drive shaft that passes through the vacuum hose to a turbine located within the vacuum hose, but outside of the duct being cleaned. As air passes through the vacuum hose the turbine and drive shaft rotate.
These prior art devices disclose the use of a rotatable brush set in motion either manually or by a drive shaft attached to a drive means. The debris loosened by the action of the brush against the internal surfaces of ducts are then aspirated by the vacuum hose. These arrangements necessitate long drive shafts or other external sources to power the brush which rub against the interior of the vacuum hose losing poser; and reduce the effective vacuum hose cross sectional area.
Accordingly there is a need for an improved device for cleaning the internal surfaces of ducts.
It is an object of the invention to overcome disadvantages of the prior art.
The above object is met by the combinations of features of the main claims, the sub-claims disclose further advantageous embodiments of the invention.